This is a veritable explosion in soccer on the diamond. But it's not the first time we've seen the world's big clubs avoid dirt and basepaths as they entertain North America's association football fanatics.

Here's a peek at what it looks like when soccer invades baseball stadiums -- including one unmissable photo from a few decades back.

Fenway Park: Celtic vs. Sporting Lisbon

Scotland's Celtic is on the attack against Portugal's Sporting during this July 2010 match. AP Photo/Elise Amendola

Fenway Park: Celtic vs. Sporting Lisbon

... and again, during that same match. AP Photo/Elise Amendola

Fenway Park: Celtic vs. Sporting Lisbon

This is from before the match, with Celtic training and the Green Monster looking on. AP Photo/Steven Senne

Citi Field: Ecuador vs. Greece

Large Greek and Ecuadorian populations in New York brought this match in June 2011. Mike Stobe/Getty Images

Citi Field: Juventus vs. Club America

A general view as the Italian side Juventus faced off against Mexico's Club America in July 2011. Jeff Zelevansky/Getty Images